package j2024.j202408;

public class j0829 {
    int[] dx  = {0,0,-1,1};
    int[] dy = {1,-1,0,0};
    int m,n;
    boolean[][] vis;

    /**
     * 200. 岛屿数量
     * @param grid
     * @return
     */
    public int numIslands(char[][] grid) {
        m  = grid.length;n = grid[0].length;
        vis = new boolean[m][n];
        int count = 0;
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if(grid[i][j] == 1 && !vis[i][j]){
                    count++;
                    dfs(grid,i,j);
                }
            }
        }
        return count;
    }
    public void dfs(char[][] g,int i,int j){
        for (int k = 0; k < 4; k++) {
            int x = i+dx[k],y = j + dy[k];
            if(x>=0 &&x<m && y>=0 && y<n && !vis[x][y] && g[x][y]=='1'){
                vis[x][y] = true;
               dfs(g,x,y);
            }
        }
    }
}
